Textbook-Integrated Guide to Educational Resources

TIGER

Sulfuric Acid into Water and IceWhen sulfuric acid is mixed with water the temperature rises. When sulfuric acid is added to ice, the temperature rises at first, but as the ice melts, the temperature falls.

Calorimetry / Thermochemistry

Endothermic ReactionSolid barium hydroxide octahydrate (Ba(OH)2*8H2O) and ammonium thiocyanate (NH4SCN) are mixed in a beaker, which is then placed on a few drops of water on a small board. The reaction that occurs is highly endothermic.

Crystallization of Supersaturated Sodium AcetateA supersaturated solution of sodium acetate is poured onto one small sodium acetate crystal. Crystals form from the liquid immediately upon contact with the seed crystal. A thermometer shows that the crystallization process is exothermic. A chemical hot pack is shown as an example of a commercially available supersaturated solution.